4. Compositions of Isometries
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Use the Triangle Inequality Theorem.
C
XY+YZ> XZ YZ+ XZ> XY XZ+ XY>YZ Applying this theorem to the given side lengths, we have three inequalities. I:& 7+9> x ⇒ 16 > x II:&9+ x> 7 ⇒ x > -2 III:& x+ 7>9 ⇒ x > 2 The range for the possible lengths of the third side can be found by looking at the overlapping regions for these inequalities.
In interval notation, this can be written as a compound inequality. 2 in.< x< 16 in. Our answer corresponds to option C.